To evaluate the quantitative human mixed lymphocyte culture (MLC) as a predictive test of renal allograft survival. The hypothesis is proposed that the magnitude to the MLC response is inversely related to the length of renal allograft survival in related and unrelated donor recipient pairs. The determination of the magnitude of the MLC response and duration of graft survival will take into account the presence or absence of both cytotoxic and blocking factors in the serum of the recipient before and after grafting. To design a new and "fast" MLC method, the results of which can be determined within 12 to 24 hours after the onset of incubation. Rapid evaluation of the MLC response is important in cadaver transplant matching.